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Even though the technology of adaptive optics (AO) is rapidly maturing, calibration of the resulting images remains a major challenge. The AO point-spread function (PSF) changes quickly both in time and position on the sky. In a typical…

The near-infrared (NIR) wavelength range offers some unique spectral features, and it is less prone to the extinction than the optical one. Recently, the first flux calibrated NIR library of cool stars from the NASA Infrared Telescope…

Solar and Stellar Astrophysics · Physics 2015-03-13 Mary Cesetti , A. Pizzella , V. D. Ivanov , L. Morelli , E. M. Corsini , E. Dalla Bonta`

With the large amounts of spectroscopic data available today and the very large surveys to come (e.g. Gaia), the need for automatic data analysis software is unquestionable. We thus developed an automatic spectra analysis program for the…

Astrophysics of Galaxies · Physics 2015-06-03 Helene Posbic , David Katz , Elisabetta Caffau , Piercarlo Bonifacio , Luca Sbordone , Ana Gomez , Frederic Arenou

A major issue in optical astronomical image analysis is the combined effect of the instrument's point spread function (PSF) and the atmospheric seeing that blurs images and changes their shape in a way that is band and time-of-observation…

Instrumentation and Methods for Astrophysics · Physics 2024-10-02 Sreevarsha Sreejith , Anže Slosar , Hong Wang

Having a need to perform differential photometry for tens of thousands stars in a several square degrees field, we developed Astrokit program. The software corrects the star brightness variations caused by variations of atmospheric…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Artem Y. Burdanov , Vadim V. Krushinsky , Alexander A. Popov

Point Spread Function (PSF) modeling is a central part of any astronomy data analysis relying on measuring the shapes of objects. It is especially crucial for weak gravitational lensing, in order to beat down systematics and allow one to…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 Joel Bergé , Sedona Price , Adam Amara , Jason Rhodes

The quantitative spectroscopy of stellar objects in complex environments is mainly limited by the ability of separating the object from the background. Standard slit spectroscopy, restricting the field of view to one dimension, is obviously…

Astrophysics · Physics 2009-11-10 Thomas Becker , Sergei Fabrika , Martin M. Roth

High-precision stellar analyses require hydrodynamic 3D modeling. Such models predict changes across stellar disks of spectral line shapes, asymmetries, and wavelength shifts. For testing models in stars other than the Sun, spatially…

Solar and Stellar Astrophysics · Physics 2021-04-28 Dainis Dravins , Hans-Günter Ludwig , Bernd Freytag

A ground-layer adaptive optics system (GLAO) uses a single adaptive mirror to partially correct the wavefront for atmospheric and telescope aberrations over a wide field of view. Instead of reaching diffraction limit on a narrow field, the…

Instrumentation and Methods for Astrophysics · Physics 2017-06-02 Donald Gavel

Optical interferometry provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Through direct observation of rotationally distorted photospheres at sub-milliarcsecond scales, we are now able to…

Solar and Stellar Astrophysics · Physics 2012-04-13 Gerard T. van Belle

Context. Stellar spectral synthesis is essential for various applications, ranging from determining stellar parameters to comprehensive stellar variability calculations. New observational resources as well as advanced stellar atmosphere…

Solar and Stellar Astrophysics · Physics 2021-09-15 V. Witzke , A. I. Shapiro , M. Cernetic , R. V. Tagirov , N. M. Kostogryz , L. S. Anusha , Y. C. Unruh , S. K. Solanki , R. L. Kurucz

Within the last years, the classification of variable stars with Machine Learning has become a mainstream area of research. Recently, visualization of time series is attracting more attention in data science as a tool to visually help…

Instrumentation and Methods for Astrophysics · Physics 2019-03-13 Christian Pieringer , Karim Pichara , Márcio Catelán , Pavlos Protopapas

In this paper, we present a deep learning system approach to estimating luminosity, effective temperature, and surface gravity of O-type stars using the optical region of the stellar spectra. In previous work, we compare a set of machine…

Instrumentation and Methods for Astrophysics · Physics 2022-10-31 Miguel Flores R. , Luis J. Corral , Celia R. Fierro-Santillán , Silvana G. Navarro

Astronomical source deblending is the process of separating the contribution of individual stars or galaxies (sources) to an image comprised of multiple, possibly overlapping sources. Astronomical sources display a wide range of sizes and…

Instrumentation and Methods for Astrophysics · Physics 2022-01-14 Ryan Hausen , Brant Robertson

Observations close to the diffraction limit, with high Strehl ratios from Adaptive Optics (AO)-assisted instruments mounted on ground-based telescopes are a reality and will become even more widespread with the next generation instruments…

Instrumentation and Methods for Astrophysics · Physics 2023-10-23 Matteo Simioni , Carmelo Arcidiacono , Andrea Grazian , Marco Gullieuszik , Elisa Portaluri , Benedetta Vulcani , Roland Wagner , Anita Zanella

The stellar population synthesis in unresolved composite objects is a very tricky problem. Indeed, it is a degenerate problem since many parameters affect the observables. The stellar population synthesis issue thus deserves a deep and…

Astrophysics · Physics 2009-11-10 J. Moultaka

Deconvolution of large survey images with millions of galaxies requires to develop a new generation of methods which can take into account a space variant Point Spread Function (PSF) and have to be at the same time accurate and fast. We…

Instrumentation and Methods for Astrophysics · Physics 2020-09-16 Florent Sureau , Alexis Lechat , Jean-Luc Starck

CONTEXT: High-precision stellar analyses require hydrodynamic modeling to interpret chemical abundances or oscillation modes. Exoplanet atmosphere studies require stellar background spectra to be known along the transit path while detection…

Solar and Stellar Astrophysics · Physics 2017-09-20 Dainis Dravins , Hans-Günter Ludwig , Erik Dahlén , Hiva Pazira

We present a method that enables wide field ground-based telescopes to scan the sky for sub-second stellar variability. The method has operational and image processing components. The operational component is to take star trail images. Each…

Instrumentation and Methods for Astrophysics · Physics 2018-11-28 David Thomas , Steven M Kahn

Recently introduced angular-memory-effect based techniques enable non-invasive imaging of objects hidden behind thin scattering layers. However, both the speckle-correlation and the bispectrum analysis are based on the statistical average…

Optics · Physics 2017-11-22 Tengfei Wu , Jonathan Dong , Xiaopeng Shao , Sylvain Gigan